alright guys, i am looking at the speed pro power-forged pistons that are in jegs right now. i am building a 350 .030 over. this motor may see a little spray or a little boost. i need to know if these pistons are worth the money. if anyone has used them, let me know what your opinions are. the compression ratio for a 64cc head is right at 9.7:1 and for $27.99 a piece, i am willing to give them a shot. probably wouldn't see more than 6-7 pounds of boost or if i ran nitrous it wouldn't be more than 100-150 shot.

 

i think they will be okay. speed pro is a good company. thats what i got, the only thing is i have hypers

 

They are very heavy......meaning they'd take a lot of abuse but it also means you cant have your piston speed very high either

its a give n take thing

 

this motor probably won't be spun any higher than 5500 but does anyone know how fast you can spin these pistons? any possibility of 6000-6500?

 

its no so much the RPM you are spinning the motor, well its part of the equation, but its the actual piston speed.

there is a formula for it

 

Korrekt. Also, I believe that the weight of the piston doesn't DIRECTLY affect an engine's redline.

Assuming that the rotating/reciprocating assy. is up to the task, you could use little anvils as pistons, and spin them at 6 grand. The limiting factor becomes the parasitic HP loss, and the durability of the bottom end.

Anybody agree/disagree?

 

wanna tell me the formula? not talking about the redline either, just shift points, will it pull to 6000? not will it just spin to 6000. my 2.8 will spin to like 7200-7400 but it stops pulling after 6000. i will be using the eagle SIR rods and the stock crank. i will not thrash this motor. i will put together a better motor when i decide to turn up the boost. with these piston though, i have the option to spray it OR boost it because of the compression ratio being so universal. so i figure a little won't hurt much.

 

Thats true, DIRECTLY, it wont affect the redline but it does indirectly and you have to be aware of that otherwise you can start throwing bearings. You can have heavy *** pistons, crank, and rods but start spinning it 7000rpm or more...but it wont last long
You kinda answered your own questions. Sure you could use it, but you said it "durability of the bottom end." It wouldn't be very durable and it would be a waste of time/money.

but

you could do it...i'm just saying you shouldn't for my above stated reasons

jim

ps....to mw66nova, i think you'll be fine with your setup. Those SIR rods are light and even with a stock weight 350 crank....you should be fine to even 7 grand. I just wouldn't push it past that

 

I'm using the same pistons in my S-10 with a .060 350 with iron crank 2 bolt mains and stock rods and have bumped the 7000 rpm rev limiter a few times when it starts gettin good to me.6500 is a normal shift in a race though.With 3.42 gears on motor it'll run a 7.80 1/8th mi.

 

thanks guys, i appreciate your time...